Bryukhanov Ilya A, Rybakov Andrey A, Larin Alexander V, Trubnikov Dmitry N, Vercauteren Daniel P
Department of Mechanics and Mathematics, Moscow State University, GSP-2 Leninskie Gory, Moscow, 119992, Russia.
Department of Chemistry, Moscow State University, GSP-2 Leninskie Gory, Moscow, 119992, Russia.
J Mol Model. 2017 Mar;23(3):68. doi: 10.1007/s00894-017-3237-8. Epub 2017 Feb 14.
The bulk and Young moduli and heats of hydration have been calculated at the DFT level for fully optimized models of all-siliceous and cationic zeolites with and without water, and then compared to the corresponding experimental data. Upon the addition of water, the monovalent alkali ion and divalent alkaline earth ion exchanged zeolites presented opposite trends in the elastic modulus. The main contribution to the decrease in the elastic modulus of the alkali ion exchanged zeolites appeared to be a shift of cations from the framework oxygen atoms upon water addition, with the coordination number often remaining the same. The contrasting increase in elastic modulus observed for the divalent (alkaline earth) ion exchanged zeolites was explained by cation stabilization resulting from increased coordination, which cannot be achieved within a rigid zeolite framework without water.
在密度泛函理论（DFT）水平下，已对含或不含水的全硅质和阳离子沸石的完全优化模型计算了体积模量、杨氏模量和水化热，然后将其与相应的实验数据进行比较。加入水后，单价碱金属离子和二价碱土金属离子交换的沸石在弹性模量上呈现出相反的趋势。碱金属离子交换沸石弹性模量降低的主要原因似乎是加水后阳离子从骨架氧原子上发生了位移，配位数通常保持不变。对于二价（碱土）离子交换沸石观察到的弹性模量的对比性增加，是由于配位增加导致阳离子稳定化，而在无水的刚性沸石骨架中无法实现这种稳定化。
